I currently am designing a console to hold most of my base radio gear, and I am running into a bit of a problem, mostly from lack of knowledge, in figuring out how to set the radios up so that I can record from them.
I want to set up the following and be able to record from them:
Motorola CDM1250 VHF
Motorola CDM1250 UHF
Motorola CDM1250 Low Band
Motorola CDM1550LS+ 200mhz
Motorola Spectra VHF Cleancab
Motorola MCS2000 800mhz
Motorola Astro Spectra 800mhz
Standard GX4800UT (2)
I would probably not be recording from more than 3 radios at once, but i'm not exactly sure how I would go about mixing the audio from all 9 radios at once so that I can call them up individually and record. Input would be to my computer to save in MP3 format. Can I wire all the radios for an external speaker, and input that audio straight into a mixer? I would like to do it without losing the internal speaker audio on the CDM's, Cleancab Spectra, and GX4800's.
Mobile radio audio mixing
Moderator: Queue Moderator
Re: Mobile radio audio mixing
Our dispatch console has most of these radios interfaced to it. There is an interface box about the size of a box of playing cards attached to the top of each radio, which is routed through an interface cable coming in from the option plug on the back of the radios. From there the audio is routed to a Dictaphone recording device. This recording device can record many "channels" on one tape, if set up properly. Our dispatch center (EMA/EMS/FD) records every public safety agency in our county, or what ever channel the radio is on.
I'll get the brands/model we use for you and post back within the next few days. I'm sure there are more members here that can inform you of their setup.
Daniel
I'll get the brands/model we use for you and post back within the next few days. I'm sure there are more members here that can inform you of their setup.
Daniel
DC615
Re: Mobile radio audio mixing
Your best bet would be to use the accessory connector that most of these radios have. Pin 11 is a fixed audio
output level on most of them. This audio level is not controlled by the front panel volume control. A coupling
capacitor of say 1.0 uf might be in order as many of these radios might have a DC bias on this fixed output
pin. You don't want to ground this pin through an audio coupling transformer. This is a must with the
MCS2000 radio.
A buffer amp with a gain of 1 might be in order to provide some isolation between the different radios. Then
combine all the different channels any way you desire.
DO NOT GROUND either speaker wire on the Motorola radios. There is a DC voltage on these wires and
you WILL BLOW the audio output amp if either wire is grounded. If you insist on using the speaker wires,
you will need an audio coupling transformer and make sure you add a series capacitor on one side of
the transformer to block the DC voltage from the radio. Again a coupling cap of 1.0 uf will do just fine.
Jim
output level on most of them. This audio level is not controlled by the front panel volume control. A coupling
capacitor of say 1.0 uf might be in order as many of these radios might have a DC bias on this fixed output
pin. You don't want to ground this pin through an audio coupling transformer. This is a must with the
MCS2000 radio.
A buffer amp with a gain of 1 might be in order to provide some isolation between the different radios. Then
combine all the different channels any way you desire.
DO NOT GROUND either speaker wire on the Motorola radios. There is a DC voltage on these wires and
you WILL BLOW the audio output amp if either wire is grounded. If you insist on using the speaker wires,
you will need an audio coupling transformer and make sure you add a series capacitor on one side of
the transformer to block the DC voltage from the radio. Again a coupling cap of 1.0 uf will do just fine.
Jim
NSPD wrote:I currently am designing a console to hold most of my base radio gear, and I am running into a bit of a problem, mostly from lack of knowledge, in figuring out how to set the radios up so that I can record from them.
I want to set up the following and be able to record from them:
Motorola CDM1250 VHF
Motorola CDM1250 UHF
Motorola CDM1250 Low Band
Motorola CDM1550LS+ 200mhz
Motorola Spectra VHF Cleancab
Motorola MCS2000 800mhz
Motorola Astro Spectra 800mhz
Standard GX4800UT (2)
I would probably not be recording from more than 3 radios at once, but i'm not exactly sure how I would go about mixing the audio from all 9 radios at once so that I can call them up individually and record. Input would be to my computer to save in MP3 format. Can I wire all the radios for an external speaker, and input that audio straight into a mixer? I would like to do it without losing the internal speaker audio on the CDM's, Cleancab Spectra, and GX4800's.